The present invention relates to a flat cutter for rolling a workpiece which consists of a pipe or solid shaft to press a spline, serration or the like to its periphery, and particularly to a workpiece bite device therein.
Hitherto, as a conventional rolling flat cutter, for example, the following is described in Japanese Patent Laid Open Publication No. 180, 635/85.
Referring to FIG. 1, a conventional flat cutter generally designated by numeral 1 comprises a rectangular solid body 2 which has a plurality of corrugated working blades 3 formed to extend in width on an upper surface thereof, and a flat portion 4 integrally formed to extend in a longitudinal direction at a starting portion 3a of the working blades 3. As shown in FIG. 2, a top of the flat portion 4 protrudes higher than the working blades 3, and a chamfer 5 and a slot 6 are formed at both sides of the flat portion 4, respectively.
At the time of working, a pair of flat cutters 1 are disposed with the working blades 3 thereof facing each other, so that a workpiece is charged for rolling between them. Since the flat cutter 1 has the flat portion 4 formed only at the starting portion 3a of the working blades 3, the workpiece is pinched by the flat portions 4 of the pair of cutters at the same time that the workpiece is worked by the starting portions 3a of the working blades 3. Therefore, there is a problem in that a large load which is produced when the bite of the workpiece starts, causes the displacement of the workpiece at the beginning of rolling and reduces the precision of working.